Vintage rear hub with sealed bearings ???
Hello. I would like to ask if you have ever seen rear hub with sealed bearings instead of tradional cup and cone bearings on such old bike. The hub has no marks or logos to help with identification. I am 100 % sure it didnt come up with the bike when it was built. It is mounted on Favorit road bike (Czechoslovakia, something around 1970). Also, when were the sealed bearings used for the first time in bike wheel hubs ? Thanks for your help
Photos here: imgur.com/a/RpRDdT8